/Engine/Source/Editor/UnrealEd/Public/ComponentVisualizer.h
Handle click modified by Alt, Ctrl and/or Shift. The input HitProxy may not be on this component.
virtual bool HandleModifiedClick ( [FEditorViewportClient](API\Editor\UnrealEd\FEditorViewportClient) * InViewportClient, [HHitProxy](API\Runtime\Engine\HHitProxy) * HitProxy, const [FViewportClick](API\Editor\UnrealEd\FViewportClick) & Click )